Many privacy doors, walls and other structures are provided with louver systems that allow passage of air from one side to the other without allowing light or visual access therethrough. Such systems by themselves are not fireproof, and when used with fireproof doors and/or fireproof walls, do not satisfy the minimum fire standards established by such organizations as the ASTN, NFPA, or UL. Because of the air passages through them, fire and smoke can rapidly move from one side of the door or wall to the other.
Heretofore attempts have been made to develop fireproof louver systems which meet fire standards. Typically, such systems include louvers which are generally flat and pivotally mounted in a frame biased by springs or weight towards a closed position. These louvers are generally held open against the spring bias or other biasing mechanism, by a so-called fusable link which will melt when subjected to heat, allowing the louvers to close. These systems are relatively complex and expensive to manufacture. In addition, problems can occur with the fusible link that prevent the louvers from closing, thereby rendering the system useless in terms of fireproofing the door or wall in which it is mounted. Another system which has been developed is disclosed in U.S. Pat. No. 6,752,714 to Lorient. In that system, a plurality of fixed slats or louvers are supported in a peripheral frame, with each of the slats being formed of a core of intumescent material coated with a thin layer of aluminum or plastic. In normal operation the slats provide spaces between them which allow air to flow from one side to the other of the louver system in the wall, door or other structure. When the device is subjected to heat the intumescent material expands that material breaking the covering layer and closing off the spaces previously formed by the slats. However, under U.S. fire standards, as established for example by ASTN, NFPA or UL, the requirement for being considered fireproof is that in a standard water test the product tested should remain intact. This requirement appears to be unique to the United States and has been part of the tests required in this country since the 1940's. The system provided by the Lorient patent does not meet fire standard requirements as established by these organizations, because it does not have structural integrity. The intumescent material is not structurally strong and cannot pass the required water pressure tests. Therefore, while it may block smoke, it is not structurally strong and is not fireproof under the established standards.
It is an object of the present invention to provide a louver structure which will meet standard fire code requirements and pass the standard water tests for fire proof systems.
Another object of the present invention is to provide a fireproof louver system which is inexpensive to manufacture.
A still further object of the present invention is to provide a method for retrofitting existing louver systems to render them fireproof in accordance with existing standards.